Hood-type annealing furnace and method for operating the same

摘要

A hood-type annealing furnace for the thermal treatment of cold-rolled steel strip includes a base, a protective hood which can be placed on the latter and under which a protective gas heated by a gas burner is circulated by a blower, to heat the steel strip, rolled up particularly into a coil, under the protective hood to a temperature of at least 500° C. in a protective gas atmosphere. An electric heater fed by the public power network has a heating capacity correspondingly substantially to the heating capacity of the gas burner. The protective gas can be independently heated with the electric heater, alternatively to the gas burner, with the gas burner switched off, to a temperature above the recrystallization annealing temperature. A method for operating a hood-type annealing furnace is also provided.

主权项

1. A hood-shaped annealing furnace for the thermal treatment of cold-rolled steel strip, the hood-shaped annealing furnace comprising:
a base; a protective hood configured to be placed on said base and to receive the steel strip under said protective hood; a gas burner having a heating capacity and being configured to heat a protective gas atmosphere; a blower configured to circulate the protective gas atmosphere heated by said gas burner under said protective hood and to heat the steel strip under said protective hood to a temperature of at least 500° C. in the protective gas atmosphere; an electric heater fed by a public power network and having a heating capacity corresponding substantially to said heating capacity of said gas burner, said electric heater configured to independently heat the protective gas atmosphere as an alternative to said gas burner to a temperature above a recrystallization annealing temperature with said gas burner switched off; and a controller configured to interrupt a supply of gas to said gas burner and activate said electric heater in the event of a surplus of electrical energy in the public power network.